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I'm wanting to get the bedrooms zoned. There is access to the supply for that area where it splits off the main run. Problem is there is no attic and this is on second floor so no access from below either to run zone thermostat wiring. I had HVAC guy come out and he said that the wire for the thermostat can be fished through the supply duct and then out of the duct into the wall in the master bedroom where the thermostat will be located. Is this possible or is this a big no no? Thanks for any help you can give on this.
Jane

hang remote control sensors in the area's you want to zone and put your dampners neat the unit where the split is. there is a zone kit available for this type application.
running low voltage wire through a duct is not a common practice and not advisable.

Tsat wire

Yes you can run stat wire
though return/air ducting.
But no you cannot run it
on the supply doct.There
is however a specific wire
you have to use to meet code.
I can't think of the rateing
right now.I have done this
many times in retro's because
of the NO other option facture.
Have fun and good luck.
41Gasman

P.S. You can always call
your city inspectors to
get the lowdown in your
area.

wire inside ductwork

running any kind of wire inside ductwork is a big no-no by any standard ! Difficult as it may be you need to find some kind of alternative.Been doing HVAC in new construction (Florida) for 13 years.Only exception inspectors allowed was a firestat behind a R/A grille.Even then it had to go directly across and exit right away.

i work in central fl and do a ton of retro's for the most part inspectors never notice it in the duct work..being that we only do it when there is little to no attic it's not like they can get in the attic or even ask about low voltage. 99.9 percent of the time they look at breakers,to see if the a/h is 4 inches off the wall,and if everything has been sealed.have a few things come up and ever inspector looks for different things but to me it seems like no biggie..i'm sure someone will say i'm wrong but it seems pretty minor..

Being new to this electrical slang... I've heard of 2 kinds of plenum rated cables.

The one I hear of the most just has a plenum rated outer shield, and I think generally it's a white covering. But someone at work swears the ONLY kind of plenum rated cable you can ever run in a plenum is the bonded/shielded plenum cable. I've never delt with the 2nd variety (not sure if thats even the correct terms, all I know is it's major bux!).

So, if you do run plenum rated cable in duct (or even in a wild return), which kind of cable do you have you use.... in general, I'm sure it varies from state to state.

Running wire in a plenum is fine if the wire is temp rated and plenum rated, it is much better off in the return but there is nothing wrong with the supply make sure you jump ground straps over any rubber boots.